Use of porous lavas as supports of photocatalysts

Porous lavas, more precisely pumice stone, are promising supports for TiO2 used as a photocatalyst. TiO2 deeply penetrates into pores that favours its retention. Its deposition is convenient and facile and the photocatalytic activity is not significantly affected by the erosion of the surface. The immobilization of TiO2 on pumice stone gave better results for the photocatalytic degradation of 3-nitrobenzenesulfonic acid than conventional sol-gel dip-coating on cement and red brick. A layer of pumice stone as pellets, fixed on a cement layer and impregnated with TiO2 is used in a thin film fixed bed reactor, for the photocatalytic treatment of water. (C) 2002 Published by Elsevier Science B.V.